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import getWeekYear from '../getWeekYear/index'
import startOfWeek from '../startOfWeek/index'
import toInteger from '../_lib/toInteger/index'
import requiredArgs from '../_lib/requiredArgs/index'
/**
* @name startOfWeekYear
* @category Week-Numbering Year Helpers
* @summary Return the start of a local week-numbering year for the given date.
*
* @description
* Return the start of a local week-numbering year.
* The exact calculation depends on the values of
* `options.weekStartsOn` (which is the index of the first day of the week)
* and `options.firstWeekContainsDate` (which is the day of January, which is always in
* the first week of the week-numbering year)
*
* Week numbering: https://en.wikipedia.org/wiki/Week#Week_numbering
*
* ### v2.0.0 breaking changes:
*
* - [Changes that are common for the whole library](https://github.com/date-fns/date-fns/blob/master/docs/upgradeGuide.md#Common-Changes).
*
* @param {Date|Number} date - the original date
* @param {Object} [options] - an object with options.
* @param {Locale} [options.locale=defaultLocale] - the locale object. See [Locale]{@link https://date-fns.org/docs/Locale}
* @param {0|1|2|3|4|5|6} [options.weekStartsOn=0] - the index of the first day of the week (0 - Sunday)
* @param {1|2|3|4|5|6|7} [options.firstWeekContainsDate=1] - the day of January, which is always in the first week of the year
* @returns {Date} the start of a week-numbering year
* @throws {TypeError} 1 argument required
* @throws {RangeError} `options.weekStartsOn` must be between 0 and 6
* @throws {RangeError} `options.firstWeekContainsDate` must be between 1 and 7
*
* @example
* // The start of an a week-numbering year for 2 July 2005 with default settings:
* var result = startOfWeekYear(new Date(2005, 6, 2))
* //=> Sun Dec 26 2004 00:00:00
*
* @example
* // The start of a week-numbering year for 2 July 2005
* // if Monday is the first day of week
* // and 4 January is always in the first week of the year:
* var result = startOfWeekYear(new Date(2005, 6, 2), {
* weekStartsOn: 1,
* firstWeekContainsDate: 4
* })
* //=> Mon Jan 03 2005 00:00:00
*/
export default function startOfWeekYear(dirtyDate, dirtyOptions) {
requiredArgs(1, arguments)
var options = dirtyOptions || {}
var locale = options.locale
var localeFirstWeekContainsDate =
locale && locale.options && locale.options.firstWeekContainsDate
var defaultFirstWeekContainsDate =
localeFirstWeekContainsDate == null
? 1
: toInteger(localeFirstWeekContainsDate)
var firstWeekContainsDate =
options.firstWeekContainsDate == null
? defaultFirstWeekContainsDate
: toInteger(options.firstWeekContainsDate)
var year = getWeekYear(dirtyDate, dirtyOptions)
var firstWeek = new Date(0)
firstWeek.setFullYear(year, 0, firstWeekContainsDate)
firstWeek.setHours(0, 0, 0, 0)
var date = startOfWeek(firstWeek, dirtyOptions)
return date
}
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